Safety device for dental units



June 24, 1958 N. E LAUTERBACH 2,840,432

SAFETY DEVICE FOR DENTAL UNITS Filed 001'.. 20, `1955 A 3 Sheets-Sheet lIN VEN TOR. NORMA/V E. LAU T E REACH BY E T June 24, 1958 N'. E.LAUTERBACH SAFETY DEVICE EoR DENTAL UNITS 5 Sheets-Sheet 2 Filed Oct.20, 1955 INVENTOR. NORMAN E LUTERBCH Arron/5r June 24, 1958 N. E.LAUTERBAcl-l 2,840,432

l SAFETY DEVICE FOR DENTAL UNITS Filed oct. zo, 1955 s sheets-sheet sJNVENTOR. NORMA/VE LAUTERBAOH VDL. K

United ,States N Pater-1f i 2,840,432 SAFETY DEVICE F R DENTAL UNITSNorman E. Lauterbach, Pittsford, N. Y., assignor to Ritter Company,Inc., Rochester, N. Y., av corporation of Delaware v 'f v Applicationoctober zo, 19ss,se1riali-10.541,642l 6 claims. (cl. S12-209) Thisinvention relates to an equipment stand and more specifically to standsof the type comprising "a unitary column or pedestal for supportingavariety of dental, medical and like equipment within convenient reach ofthe user adjacent the place of use. Reference is made to Patent No.2,690,945 issued October 5, 1954 to FayV is again actuated to retractthe equipment withinnthe equipment stand and close the door toy protectthe instruments from dust and possible damage when in an exposedposition.v Notwithstanding the fact that initiation of the operation ofthe motor is by a switch within the convenient reach of the dentist, ithas been Yfound in practice that a dentist will occasionallyinadvertently or carelessly endeavor to open or force the door manuallyto enable access to the instruments. Moreover, it has been found inpractice that occasionally one of the instruments may not be fullyretracted within the instrument holder when the dentist presses theswitch to close the door and the instrument or its cord may be caughtbetween the edge of the door and the margin of the opening in theequipment stand which the door closes. In the mechanism of that patentthe connection between the motor and the instrumentvholder is such thatwhen this occurs the `mechanism will become jammed and bent or the motorshaft will be snapped oil. I vAn yobject of my invention is to overcometh'e diiliculties above set forth with the structure shown in the-Bronkpatent when the equipment is carelessly operated.

Another object of my invention is to provide in the linkage between themotor and the door and instrument holder, a connection which isautomatically broken when an attempt is .made to manually force opensaid door or when an objectbecomes caught between the edge of the doorandthe margins of the opening which the'door closes. l

More specifically, my invention contemplates thefemployment of a noveltoggle construction in the mechanism of the above mentioned patent whichwill break when an undue strain is placed upon the mechanism or themotor is overloaded due to careless or inadvertent operation of themechanism.

Other objects and advantages be pointed out in the claims and will beapparent from the following description, when taken in connection withthe accompanying drawings, in which:

Fig. l is a view showing the interior of the equipment stand in whichthe instruments are normally housed,l

showing the instrument holder retracted and the door in' its closedposition, the view showing onlysuch portionv yof my invention willyofthe equipment stand with which the invention is concerned;

Fig. 2 is: a view similar to Fig. 1 with the holder and the instruments,in their projected position and with the door open; f t

Fig. 3 isv a view the connections between the motor and the instrumentholder and door are broken Y less use of the equipment;

VFig. 4 is a top plan View oflva part of the linkage shown in Figs.; lto `3inc1usive and showing the'toggle link whichs ffbroken when an`attempt is made to force the door open manually;

Fig. 5 Vis asectional -viewv taken substantially on thev line 5-5 ofFig. 4 in the direction indicatedV by the arr0W;f

Fig. 6 is a view showing aportion of the linkage and in particular thetoggle link of Figs. 4 and 5, the view showing the parts in the positionwhich they occupy when the door is` closed and the instrument holderretracted;

Fig. `7 is a view similar to Fig. 6, the links being shown intheposition which they occupy when the dooris open andthejinstruments-projected; e Y

Fig. 8 is a view similar to Figs. 6 and 7 but showing the position oftheparts when the toggle has been broken,

, the view corresponding to the position of the parts shown arm and its'associated table and other appurtenances' common in the art. AllV of theelements Vdisclosed in this application andtheiroperation will not bedescribed in detail, reference to the abovementioned patent being hadfor that purpose.V

' Referring toFigs. 1 and 2, the equipment stand com prises a housing 11having an opening `12, and a holder 13 having sockets for the receptionof a plurality of dental or medical instruments 14. The stand includes adoor 16 and a plurality of retractable cords or cables 17 which enablethe individual instruments 14 to be pulled out of their holder and -beautomatically retracted into the holder when released as is commonpractice in the art.

The holder 13`is supported for movement to project it forwardly throughthe opening 12 as will be apparent from comparison of Figs. l and 2,opposite sides of the holder having trunnions 18 serving to pivotallyconnect the holder between spaced arms 19 which are bridged through aportion of their extent by a panel 21. The panel carries certaincontrols not necessary to describe herein and when the instruments arein extended position as shown in Fig. 2, the panel closes the openingabove the holder.

The Side walls of the panel 21 have their upper ends extended to providespaced'arms 22 whichV are pivoted on studs or trunnions 23 which aresupported internally of the equipment stand. Arms 22 are extended beyondtheir pivots 23 to form fingers 24 each having its end connected to acounterbalance spring 26. A second set of springs 27.is connectedbetween the ends of the fingers 24 and The door iciscarried'by a pair ofspaced` arms 34 2,840,432 Patented June k24, 19,58 n

showing the position of the parts whendue to incorrect orcareupstandingelements ,31 torminsg; ,av carnigroove 38 in which aroller 39' rides. These' rollers 39 are rotatably supported'- inbracketscarrjed by thearms 2r9,

' The .mechanism .described fis actuatedgby a' motoridiagrammaticallyillustrated at 41. 0n the endY ofthernotor shaft an actuatingAelementr42 isprovided having VJthree arms 43, 44 and 46.1Two ofthese,arms 43' and 444 actuateV micro-switchesjwhileffthethird arnr 46 servesas Aa crank arm. 'Reference-is made' to theabove mentioned patentrfor adisclosure of the motor fircuitlandits'asso ciatedipalts;itbeingsncientto state herein 'that a manual switch locatedwithin convenientgreachofthedentistcon trois the automaticrswitches to initiate-movement' of theYparts from` one position Vto`anotherbthatffis from the'posi'- tionshownsinFigfl; to }that shwninf1-`ig, 2 or `reverse. Uponeachactuatifniofr the manual switchVVV the -actuator 42 rotates through180`degrees. The circuit and switches are varranged so? that Luponractuation-'of the manual switch and u.the -completion of Y l-8O'degrees of rotational operation,V

motor operation Yis,y discontinued. crank arrntKY-is connectedbytoggle'link-means,y generallydndicated by the numeral V47, to theVpanel 21 as shown atr48. "'The detailsv rofthis toggle linkggmeansconstituteddhe irnprovement of my invention'rand Zha'sybeen shown 4to-9inclusive; s v It is believedtthat 4the'loperation of the-mee'hanism'from the foregoing description;r particularly'upon;reference Vto the vabove mentioned Apatent will be understood. WinniVthe partsaare intheypositionshown in-Fig. 21, abr'ief closure ofthemanual switch serves to startthe motorand close the automatic switchuntil the partsreaeh=the` pro` jectedA position 4of use shown in Fig. 2lat which timelfthe operation -of :the motor vbrings .about the "openingof=the circuit and arrests the-movement of the parts. Suchoperationfirst-swingsthe-.covenor door to atleast a partially or Vdentist`standing orse'ated .fomthe opposite sidenofa dental chairinwhich arpatient .is seated. Afteruseof the instruments carried :by' .thefholder, a .second voperation `.of the manual switch retracts the,instrument holder:and lcon. trol panel .andcompletely closes the,housing :opening to v protect the lparts, exclude .dustand maintainthe.

motor shaft. `A similar result rnayroccur if the dentistV has aninstrument in `an Vextended position `with respect to the holder and`releases .the instrument for retraction:

into the holder while at the same time pressing y.the-manual switch. Theinstrument may .then be between the upper edge. of the door'and vthe.margin of the opening which it closes, that is, adjacent the point S1(Figi).

Due tothe inadvertenee orcarelessness .of dentists in operation of theirequipment, it has been .found desirable or necessaryto' provide meansfor protecting the equip. ment should it beimproperly operated. Y Suchmeansrcomf. prises the toggle iink means 47 .shown 4in Fig`s.4 vto 9Yinelusive..`

As shown most .cl'early zin Figs. @tand `5:.the .toggle link. means:47.".c`omprisesran arm S2. The arm. 52 has .ax

bottonrwall 53 and a pair. of upstanding .sidewalls v54'.

A pivot rod :.56 constituting the pivot 48 (see Figs. Land` 2) extendsthrough the .sidewalls 54. A pivot pint57" extendsethrough thesidewallsat the opposite end of lthe arm 52.` The sidewalls 54 arenotched as shown at 58 to accommodate a pin V59 mounted on the end ofthe actuating arm 46. The pin 59 is adapted to pivotally receive atoggle link 61 which lies between the sidewalls 54 of the arm 52 and ispivoted on the pin 57. A spring 62 somewhat S shaped having one endsecured to the toggle link, as shown at Y63, `isV confined by a pin 464extending between the sidewalls 54. The spring retains the toggle link61 in the position shown in'Fig. 5. Adjusting means, shown at 6 6,determines the .position .to 'which .the spring .62 will urgefthe.toggle 1ink\61. lBy threading `inward or outward on the adjusting means66 theetect-of the spring 62 may be `decreased .or increased. Uponthreading the adjusting means inward, the toggle inay be broken moreeasily.

ln Fig. 5 I have drawnV two lines A and B. Line A extends through thepin 64 and pivot 57. It will be noted. that the point 63 of attachmentof thespring-to the tQggle link lies `he'low .this line. Thus the.spring retains 'the toggle link '51' below a' dead center positionrepresented by the line A. The 'line B extends through the center of thepivot rod 56 and through the pi'votpin 57. The center of the Apin 59liesslightly above this '.line

I B.V Thus the force of the motor, rotating thevactuating' .openposition: andswin gs@the holder and panel ftd-the' advanced positionshown -in` Fig. 2 in l which 'position 4the instruments projected withineasyrneachof the operatorarm 46, tends to break the ltoggle while theforce of the spring j62"overcomes the -force o'f the motor vand retainsthe'toggle Vin the position' shown in Fig. 5 unless 'the motor becomesoverloaded by reason, for example, ofan instrument or other object beingcaught between Vthe upper edge ofthe door Aand the margin ofthedooropen'- ing." Such overloading of the motor 'will' cause an up-Yward"force on the pin 59A and break the toggle."

In fFig's flfhave shown the 4parts of the togglelirik means 4T-and Iits`associated parts in the position which they occupy-when the door 'isclosed as will be :evident from a comparison of Figs. 'l and 6. LikewiselIfhave' shown the Vposition of the parts in Fig. 7 when 4the door isopen which will be evident 'from a comparison ofFigs; 2 and 7. lIn sFig.v8 I ha-Veshown the ltoggle broken. In this position -of the parts 'theload on the motor duejto` jamming A.of the Amechanism `has caused 'theforce -exerted by theMrnotor` on the pin 159 to overcome'the Aspring 62jand` .brealr 4the toggle. The rigid connection' between the actuator4146i and vthe panel' Z1 :is then 4`tlestreyed'tci` thereby preventbending-of the links or 'thersnapping of the 4motor-shaft. When ythetoggle hasbeen brolten, as illustrated inFig. 38, due Ito the 'lackefr-a lrigid con` neet-ion. between, the parts, ithe door and theinstrument holderimay'drop :to `the position shown in 'Brand :anyyobstruction .may .bey removed. The entire mechanism Fist j ofmyinventionit '-.wll `be .apparent `thatuzarious v.modificaan electric motor and aninstrument holder, means intercpnnectingsaid motor .and holder `forprojecting the holder from a posi-tion withinthe equipment stand to anvexternalposition with respectt'hereto, means including a manuallyoperated switch for initiating the operation of Vthe motor and a makeand"brcak` toggle 'in said inter" connecting means for (protecting themotor should it become overloaded;` said toggle 'including [two elementspivoted to eaehother `one of which is connected to the t motor andthe'otherof which is-connectcd .tothe holder,

a 'stopbetween said. members, a `spring for normallyholding1 one offsaid Vmembers against said stop and lin a .bel'` y'ond dead centerposition and means including said motor for throwing said member awayfrom said stop and to the other side of the dead center position shouldthe motor become overloaded.

2. Mechanism of the character described comprising, in combination,motor means, a crank arm driven by said motor means, a pivoted armadapted to support and swing an object to be shifted from one positionto another position upon one cycle of the motor means and returned toits original position upon a succeeding cycle of said motor means, linkmeans pivoted to said arm and having connections to said crank arm whichconnections include a make and break toggle, said make and break togglecomprising a toggle link having a pin which pivotally connects thetoggle link to the crank arm, a pivot between said toggle link andsaid'link means, a spring biasing said pin and toggle link into aposition such that a driving connection is formed from the motor meansto said pivoted arm through said link means during normal operation ofthe mechanism, the force of said motor means when overloaded overcomingthe spring bias to break said driving connection which condition ofmotor means overload may be occasioned by a resistance to the freeswinging movement of said arm.

3. Mechanism in accordance with claim 2 in which operation of the motormeans is controlled by a switch which upon actuation initiates rotationof the motorv means which then rotates through 180 degrees after whichthe driving force of the motor is discontinued.

4. Mechanism in accordance with claim 2 in which the pivot connection ofsaid link means and the'pivot connection of said toggle link to saidlink means form a 6 line andthe spring normally biases the toggle linkto a position on'one side of `said line while the rotational force ofthe motor means tends to move the toggle link to the `other side of saidline, the force of said spring being suicient to overcome the torque ofthe motor means under normal conditions of operation but insuflicient to`overcome the force of the spring should an overload be imposed upon themotor means.

5. Mechanism in accordance with claim 2 in which the pivot connection ofsaid link means and the pivot connection of said toggle link to saidlink means form a line and the spring normally biases the toggle link toa position on one side of said line while the rotational force of themotor means tends to move the toggle link to the other side of saidline, the force of said spring means being suicient to overcome thetorque of the motor means under normal conditions of operation but beingsuicient tofovercome the force of the spring should an overload beimposed upon the motor means and means for adjusting the position towhich said spring biases said toggle link on the rst mentioned side ofsaid line.

6. Mechanism in accordance with claim 2 in which means are provided formaking said toggle upon the next cycle of said motor means if theresistance to the free movement of said arm has been removed.

References Cited in the le of this patent UNITED STATES PATENTS1,167,805 Elliott June 11, 1916 2,280,246 McCullough Apr. 21, 19422,690,945 Bl'onk Oct. 5, 1954

